Dynamic events

[davearia]

Hi All,

 

Here is a snippet of some code I have been playing around with this morning.

Private Sub designIndividualTabPages(ByRef TabPage1 As TabPage, ByVal dsQuestions As DataSet, ByVal dsAnswers As DataSet)
       Dim counter As Int32
       Dim xCoordForLabel As Int32 = 10
       Dim yCoord As Int32 = 10
       Dim xCoordForComboBox As Int32 = 150
       If dsQuestions.Tables.Count > 0 Then
           If dsQuestions.Tables(0).Rows.Count > 0 Then
               Try
                   For counter = 0 To (Convert.ToInt32(dsQuestions.Tables(0).Rows.Count - 1))
                       Dim lbl1 As New System.Windows.Forms.Label
                       lbl1.Location = New System.Drawing.Point(xCoordForLabel, yCoord)
                       lbl1.TabIndex = counter
                       lbl1.Text = Convert.ToString(dsQuestions.Tables(0).Rows(counter).Item(0))
                       lbl1.Name = "label" + Convert.ToString(counter)
                       TabPage1.Controls.Add(lbl1)
                       Dim ComboBox1 As New System.Windows.Forms.ComboBox
                       ComboBox1.Location = New System.Drawing.Point(xCoordForComboBox, yCoord)
                       ComboBox1.TabIndex = counter
                       ComboBox1.Name = "cbo" + Convert.ToString(counter)
                       ComboBox1.Size = New System.Drawing.Size(121, 21)
                       populateComboBox(ComboBox1, dsAnswers)
                       TabPage1.Controls.Add(ComboBox1)
                       yCoord += 30
                   Next
                   Dim Button1 As New System.Windows.Forms.Button
                   Button1.Name = "btn" + Convert.ToString(counter)
                   Button1.Location = New System.Drawing.Point(100, 140)
                   Button1.Text = "Submit"
                   'How do I create a event handler for the click event of this button
                   TabPage1.Controls.Add(Button1)
               Catch ex As Exception
                   MessageBox.Show("Error whilst putting controls on tab page")
               End Try
           End If
       End If
End Sub

 

Basically this code is part of a user control. Based on what the dataset dsAnswers contains each tab page will dynamically create a label, a comboBox and a button for each row in the dataset. All of which works perfectly.

 

The problem I have is creating/accessing events. For example where I have put the comment 'How do I create a event handler for the click event of this button in the code, how would I create this event for each button?

 

Any help is greatly appreciated.

 

Thanks, Dave. :D :D :D

[Cags]

You can't dynamically create a method for each one. What you should be doing is creating a generic sub that will deal with all buttons, you will then attach that sub as the event for each one. The assuming you use an overload similar to the standard .Net Framework ones, you can find out exactly which button has called the event, and then filter what todo for that button using either a switch statement or whatever.

[davearia]

Thanks for the reply Cags.

 

I understand the logic of what you are saying. But what is the syntax of the solution you described. Could you be so kind as to give me some code as an example?

 

Thanks Dave. :D :D :D

[Cags]

Well it's very difficult to provide an example of the code without actually knowing what exactly you want the event todo. I can give you an example of attaching an event (in case you don't know how todo this).

' create an event like so
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
       ' stuff todo when event fired
   End Sub

' in your code you attach the event with
AddHandler Button1.Click, AddressOf Button1_Click

I think it's right, I'm a C# person myself though. Basically what the code does is attaches the sub Button1_Click to the Click event of an object called Button1.

[davearia]

Thanks mate,

 

Think you solution is little more straightb forward but I got a fix as well. I got round it another way:

I created a userControl that inherited the class Button. I just added the following the new class.

Public Sub mySub(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Click
       MessageBox.Show(Me.Name)
End Sub

It fired ok.

 

Tried your code and that is good too. So as usual there is always more than one way of doing this.

 

Thanks again, Dave. :D :D :D